Submits a block to a dispatch queue for multiple invocations.
- iOS 4.0+
- macOS 10.6+
- tvOS 9.0+
- watchOS 2.0+
The number of iterations to perform.
The queue on which to submit the block. This parameter cannot be
The application-defined function to be submitted. This parameter cannot be
This function submits a block to a dispatch queue for multiple invocations and waits for all iterations of the task block to complete before returning. If the target queue is a concurrent queue returned by
dispatch_get_global_queue, the block can be invoked concurrently, and it must therefore be reentrant-safe. Using this function with a concurrent queue can be useful as an efficient parallel
The current index of iteration is passed to each invocation of the block.